Staging Environment: Content and features may be unstable or change without notice.
Advisory details: gitlab / maven/io.netty/netty-handler/CVE-2026-44249
Advisory ID gitlab/maven/io.netty/netty-handler/CVE-2026-44249
Aliases CVE-2026-44249
GHSA-3qp7-7mw8-wx86
Summary Netty has an IPv6 Subnet Filter Bypass via Incorrect Comparator Masking An attacker can bypass IPv6 subnet rules due to an incorrect masking operation in IpSubnetFilterRule.compareTo(). Valid public IP addresses can bypass the restrictions.
Status Published
Exploitability 0.5
Weighted Severity 0.0
Risk
Affected and Fixed Packages Package Details
Introduced and Fixed Package Commit Patches Package Commit Patches Details
Weaknesses (4)
CWE-284 Improper Access Control
CWE-697 Incorrect Comparison
CWE-937 OWASP Top Ten 2013 Category A9 - Using Components with Known Vulnerabilities
CWE-1035 OWASP Top Ten 2017 Category A9 - Using Components with Known Vulnerabilities
System Score Found at
cvssv3.1 https://gitlab.com/gitlab-org/advisories-community/-/blob/main/maven/io.netty/netty-handler/CVE-2026-44249.yml
Reference id Reference type URL
https://github.com/netty/netty/releases/tag/netty-4.1.135.Final
https://github.com/netty/netty/releases/tag/netty-4.2.15.Final
https://github.com/netty/netty/security/advisories/GHSA-3qp7-7mw8-wx86
CVE-2026-44249 https://nvd.nist.gov/vuln/detail/CVE-2026-44249
GHSA-3qp7-7mw8-wx86 https://github.com/advisories/GHSA-3qp7-7mw8-wx86
No exploits are available.

No EPSS data available for this advisory.

Patch URL
There are no known patches.
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H Found at https://gitlab.com/gitlab-org/advisories-community/-/blob/main/maven/io.netty/netty-handler/CVE-2026-44249.yml
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none

Vector: SSVCv2/E:N/A:N/T:T/P:M/B:A/M:M/D:T/2026-06-13T02:42:49Z/

Decision: Track

Source URL: https://github.com/cisagov/vulnrichment/blob/develop/2026/44xxx/CVE-2026-44249.json

Source Advisory: vulnrichment/CVE-2026-44249

View SSVC decision tree 
[{'Exploitation': 'none'},
 {'Automatable': 'no'},
 {'Technical Impact': 'total'},
 {'Mission Prevalence': 'minimal'},
 {'Public Well-being Impact': 'material'},
 {'Mission & Well-being': 'medium'}]